TmS4

At WOT the boost peaks to 20psi and then bounces down to 10psi and bounces back to 20psi it keeps bouncing back and forth until it hits 4000rpm then on its way down it catches at 16psi and tapers to red line like normal. I can feel the power surging so I know it not just my boost gauge If I don't go WOT until 4000rpm it just spikes to 20psi and then holds at 16psi and tapers. I replaced my N75 thinking that was the problem it was not and my MAF was on its way out and I replaced that too. I put on a MBC and the problem would stop happening at lower rpms, when I set the MBC to around 17psi the problem would stop at 3000rpm, when I dialed the MBC back to 15psi the problem would not happen over 2600rpm. When I would floor it at lower rpms, under 3000rpm where the boost does not come up right away the boost would not go as high. The boost would be 2 psi lower than what the MBC was set at, but if when it did get above 3000rpm I quickly lifted off the throttle a little bit and then stomped on it again the boost would come on where I had set the MBC too. When I put the IBE on stock mode or put in my stock ECU I have the same problem of the boost being 2 psi low if I go on at low rpm and I can fix it the same way by lifting off quickly. I have done some logging with my friends vag-com and I had throttle cut when the boost was cutting. I did not have any codes. I do not have a boost leak.
Second problem I am having.
Somewhat rough idle, both with a/c on and off some misfires cylinder 4 and 6 at idle. Intermittent difficulty starting it cranks for 5 seconds and never catches, but will start if I stop and try again. No codes on VAG. spark plugs are fairly new, I put on ignition solution coils and new battery no help.

JBear::FATS

Have you pressure tested ?

Have you checked for DTC's, this would be really helpful.

TmS4

No K04's, no DTC's, and no boost leak.

JBear::FATS

I personally would consider removing the MBC, only because it would make it easier to troubleshoot.

I wonder if your BPV's are not holding boost, and are opening or possibly the N249 is on it's way out.

Pop3

have you checked f-hose or pressuretested the intake?

back2black

only restarting or resetting ecu would make it work. Pretty much decides when it wants to boost high or not. no codes, no limp mode... faulty n75?

dscottjr

You need piggies circuit. Search for mr.piggie and email him with your problem. he can fix it.

VerrÜckt

Email mike01s4@yahoo.com